Patent Application
20240181678
The present invention mainly relates to a manufacturing method of a sheet molding compound (SMC).
The present invention also relates to a dispersion roller device suitably used for manufacturing an SMC, and an SMC manufacturing apparatus comprising the same.
This application is a continuation application of International Application No. PCT/JP2022/021029, filed May 20, 2022, which claims the benefit of priority of the prior Japanese Patent Application No. 2021-118818, filed Jul. 19, 2021, and Japanese Patent Application No. 2022-050649, filed Mar. 25, 2022, the contents of which are incorporated herein by reference.
Carbon fiber reinforced plastic (CFRP) is a lightweight composite material with excellent mechanical properties, which is suitable for parts of manned aircraft, unmanned aircraft, automobiles, ships, railway vehicles, and other transportation equipment, and its importance has been increasing in recent years.
An intermediate material referred to as “prepreg” is preferably used when manufacturing CFRP products by compression molding. Prepregs for CFRP products are produced by impregnating a carbon fiber reinforcement with an uncured thermosetting resin composition.
CF-SMC is one type of prepreg, and its manufacturing process involves cutting a continuous carbon fiber bundle with a chopper into short carbon fiber bundles, which are then allowed to fall onto a carrier film travelling with its surface oriented approximately horizontal, to thereby forma carbon fiber mat. CF-SMC is manufactured by impregnating this carbon fiber mat with a thermosetting resin composition.
As regards manufacturing of CF-SMC, it has been proposed to provide a dispersion roll below a chopper in order to disperse short carbon fiber bundles that are let to fall onto a carrier film (Patent Literatures 1 and 2).
The present invention relates to an SMC manufacturing technology that uses a dispersion roll to disperse short fiber bundles that are allowed to fall onto a carrier film, and its primary purpose is to provide an improvement that is advantageous in achieving at least one of the following: preventing contamination of the SMC manufacturing line, maintaining the cleanliness of mechanical elements included in the SMC manufacturing apparatus, preventing failure of control equipment installed in or around the SMC manufacturing apparatus, and preventing deterioration of the working environment.
In the present specification, problems that can be solved by each embodiment of the present invention may be explicitly or implicitly disclosed.
The present invention in its one embodiment provides a manufacturing method of a sheet molding compound, comprising (i) allowing short fiber bundles to fall onto a carrier film travelling with its surface oriented approximately horizontally, while dispersing the short fiber bundles using a dispersion roller device having a rotationally driven dispersion roll, two bearings supporting the dispersion roll, a first side cover, and a second side cover, thereby depositing a fiber mat on the carrier film, and (ii) impregnating the fiber mat with a thermosetting resin composition, wherein the dispersion roller device has a configuration in which the first side cover and the second side cover are disposed between the two bearings; the dispersion roll comprises a roll body, a first roll body-adjoining part, and a second roll body-adjoining part, wherein the roll body comprises a cylinder and a plurality of pins provided on a circumferential surface of the cylinder, and the first roll body-adjoining part and the second roll body-adjoining part respectively adjoin one end and the other end of the roll body in its axial direction; and an inner circumferential surface of a circular opening provided in the first side cover and a cylindrical circumferential surface of the first roll body-adjoining part face each other, while an inner circumferential surface of a circular opening provided in the second side cover and a cylindrical circumferential surface of the second roll body-adjoining part face each other.
The present invention in its another embodiment provides a manufacturing method of a sheet molding compound, comprising (i) allowing short fiber bundles to fall onto a carrier film travelling with its surface oriented approximately horizontally, while dispersing the short fiber bundles using a dispersion roller device having a rotationally driven dispersion roll, two bearings supporting the dispersion roll, a first side cover, and a second side cover, thereby depositing a fiber mat on the carrier film, and (ii) impregnating the fiber mat with a thermosetting resin composition, wherein the dispersion roller device has a configuration in which the first side cover and the second side cover are disposed between the two bearings; the dispersion roll comprises a roll body, a first roll body-adjoining part, and a second roll body-adjoining part, wherein the roll body has n-fold rotational symmetry around its rotation axis, with the proviso that the n is a finite integer of 1 or more and may be 72 or less, and the first roll body-adjoining part and the second roll body-adjoining part respectively adjoin one end and the other end of the roll body in its axial direction; and an inner circumferential surface of a circular opening provided in the first side cover and a cylindrical circumferential surface of the first roll body-adjoining part face each other, while an inner circumferential surface of a circular opening provided in the second side cover and a cylindrical circumferential surface of the second roll body-adjoining part face each other.
The present invention in its still another embodiment provides a dispersion roller device used for dispersing short fiber bundles allowed to fall onto a carrier film in production of a sheet molding compound, comprising a rotational drive dispersion roll, two bearings supporting the dispersion roll, a first side cover, and a second side cover, wherein: the first side cover and the second side cover are disposed between the two bearings; the dispersion roll comprises a roll body, a first roll body-adjoining part, and a second roll body-adjoining part, wherein the roll body comprises a cylinder and a plurality of pins provided on a circumferential surface of the cylinder, and the first roll body-adjoining part and the second roll body-adjoining part respectively adjoin one end and the other end of the roll body in its axial direction; and an inner circumferential surface of a circular opening provided in the first side cover and a cylindrical circumferential surface of the first roll body-adjoining part face each other, while an inner circumferential surface of a circular opening provided in the second side cover and a cylindrical circumferential surface of the second roll body-adjoining part face each other.
The present invention in its still another embodiment provides a dispersion roller device used for dispersing short fiber bundles allowed to fall onto a carrier film in production of a sheet molding compound, comprising a rotational drive dispersion roll, two bearings supporting the dispersion roll, a first side cover, and a second side cover, wherein: the first side cover and the second side cover are disposed between the two bearings; the dispersion roll comprises a roll body, a first roll body-adjoining part, and a second roll body-adjoining part, wherein the roll body has n-fold rotational symmetry around its rotation axis, with the proviso that the n is a finite integer of 1 or more and may be 72 or less, and the first roll body-adjoining part and the second roll body-adjoining part respectively adjoin one end and the other end of the roll body in its axial direction; and an inner circumferential surface of a circular opening provided in the first side cover and a cylindrical circumferential surface of the first roll body-adjoining part face each other, while an inner circumferential surface of a circular opening provided in the second side cover and a cylindrical circumferential surface of the second roll body-adjoining part face each other.
There is provided an improvement advantageous in achieving at least one of the following: preventing contamination of the SMC manufacturing line, maintaining the cleanliness of mechanical elements included in the SMC manufacturing apparatus, preventing failure of control equipment installed in or around the SMC manufacturing apparatus, and preventing deterioration of the working environment.
One embodiment of the present invention relates to a sheet molding compound (SMC) manufacturing apparatus that can be preferably used in a method of manufacturing an SMC comprising the following (i) and (ii), particularly in a method of manufacturing a CF-SMC:
Referring to
The first applicator 20 is used to apply a first resin paste 5a to a first carrier film 4a to form a first resin paste layer 6a.
The second applicator 30 is used to apply a second resin paste 5b to a second carrier film 4b to form a second resin paste layer 6b.
The chopper 40 is disposed above the conveyance path for the first carrier film 4a and is used to cut the continuous fiber bundle 1 into short fiber bundles 2.
Below the chopper 40, the surface of the first carrier film 4a on the conveyance path is held substantially horizontally. This is to prevent the fallen short fiber bundles 2 and the deposited fiber mat 3 from moving due to gravity on the surface of the first carrier film 4a.
The chopper 40 is of a type that is also used in conventional SMC manufacturing apparatuses, and has a cutter roll 41, a receiving roll (rubber roll) 42, and a guide roll 43.
The rotation axes of the cutter roll 41, the receiving roll 42, and the guide roll 43 are all parallel to the T direction.
The T direction is a direction that is horizontal and perpendicular to the M direction. The M direction is the travelling direction of the first carrier film 4a.
The T direction is perpendicular to the paper surface in
The dispersion roller device 50 is disposed below the chopper 40 in order to disperse the short fiber bundles 2 falling onto the first carrier film 4a.
A laminator 70 for laminating the first carrier film 4a and the second carrier film 4b is disposed upstream of the impregnator 60.
The laminator 70 laminates the first carrier film 4a and the second carrier film 4b together to form a stack 7. In the stack 7, a first resin paste layer 6a, a fiber mat 3, and a second resin paste layer 6b are sandwiched between the first carrier film 4a and the second carrier film 4b. The impregnator 60 is of a type used in conventional SMC manufacturing apparatuses, and has two belt conveyors (upper and lower belt conveyors) for conveying the stack 7 sandwiched between two conveyor belts, and rolls for pinching and pressurizing the stack 7 together with the conveyor belts.
Both the side cover (right) 53 and the side cover (left) 54 are disposed between the bearing B1 and the bearing B2. Therefore, the side covers and the bearings are not integrated.
In the present specification, as shown in
As shown in
The roll body 510 is of a pin roll type and has a cylinder 510a and a plurality of pins 510b arranged on the circumferential surface of the cylinder 510a.
Both the roll body 510 and the shaft 511 of the dispersion roll 51 have high rigidity and are formed of a metal material such as stainless steel.
The pins 510b move in the circumferential direction when the dispersion roll 51 is rotated, which allows the short fiber bundles 2 to be hit by the side surfaces of the pins 510b.
Both the roll body-adjoining part (right) 513 and the roll body-adjoining part (left) 514 have cylindrical circumferential surfaces. The material of the roll body-adjoining parts may be different from or the same as that of the cylinder 510a. When the material of the roll body-adjoining parts is different from that of the cylinder, the material of the roll body-adjoining parts may be a metal (including alloys; the same shall apply hereinafter), or the roll body-adjoining parts may be formed entirely or partially of a resin. When the roll body-adjoining parts and the cylinder are formed of the same material, the roll body-adjoining parts 513, 514 may be formed integrally with the cylinder 510a.
The diameter of the cylindrical circumferential surface of the roll body-adjoining parts 513, 514 is larger than the diameter of the shaft 511, and may be the same as or different from the diameter of the cylinder 510a. Preferably, the diameter of the cylindrical circumferential surface of the roll body-adjoining parts 513, 514 is equal to or larger than the diameter of the cylinder 510a. In one example, the radius of the roll body-adjoining parts 513, 514 may be equal to or greater than the maximum radius rM of the roll body 510. The maximum radius rM of the roll body 510 is the radius of a cylinder whose central axis coincides with the rotation axis of the roll body 510 and which circumscribes the roll body 510. In the case of a pin roll type, the maximum radius of the roll body is equal to the distance from the rotation axis to the tip of the longest pin.
The diameter of the roll body-adjoining parts 513, 514 may be significantly smaller than the diameter of the cylinder 510a, which, however, may pose a disadvantage that the gap formed between the cylinder 510a and the side covers 53, 54 is easily contaminated with fiber dust, and is not easily cleanable.
A preferred embodiment of the pin roll type roll body 510 is as follows.
The diameter of the cylinder 510a is, for example, but not limited to, 30 mm to 300 mm, and may be 60 mm to 150 mm. A larger diameter of the cylinder 510a allows the whole pin 510b to move at a higher circumferential speed when the dispersion roll 51 is rotated, resulting in higher ability to disperse the short fiber bundles 2.
The pin 510b extends perpendicularly to the rotation axis (central axis) of the dispersion roll 51, and may have, for example, but without limitation, a cylindrical shape. The boundary between the end surface and the circumferential surface of the pin 510b may be chamfered.
The diameter of the pin 510b is, for example, but not limited to, 1 mm to 15 mm, and may be 10 mm or less, preferably 5 mm or less.
The length of the pin 510b, that is, the distance from the tip to the base of the pin, is, for example, but not limited to, 10 mm to 150 mm, and may be 10 mm to 100 mm, or may be 10 mm to 50 mm.
Preferably, all of the pins 510b have the same shape and dimensions as each other.
The arrangement of pins 510b on the circumferential surface of cylinder 510a is periodic. When the arrangement of the pins 510b is shifted, for example, in the axial direction of the cylinder by 5 mm or more and less than 20 mm, 20 mm or more and less than 40 mm, or 40 mm or more and 60 mm or less, and also when it is shifted in the circumferential direction of the cylinder by, for example, 10°, 15°, 18°, 20°, 22.5°, 30°, 45°, 60°, 90°, 120° or 180°, it may overlap with the original arrangement. In the example of
In the dispersion roll 51 shown in
In another typical example, as shown in
In one example, as shown in
The side cover (right) 53 and the side cover (left) 54 are preferably, but not limited to be, formed of metal plates. When a metal plate is used, its thickness is, for example, 3 mm to 5 mm, and may be larger or smaller than this range depending on the required rigidity and strength.
On both the right and left sides, the horizontal distance Ds from the side cover 53, 54 to the pin 510b which is closest to the side cover in terms of horizontal distance is 60 mm or less, 50 mm or less, 40 mm or less, 30 mm or less, 20 mm or less, or 10 mm or less.
As shown in
By adopting such a configuration, the short fiber bundles 2 and the fiber dust generated by dispersing the short fiber bundles 2 with the dispersion roll 51 become less likely to leak to the outside of the side covers 53 and 54. This is advantageous in achieving at least one of the following: preventing contamination of the SMC manufacturing line, maintaining the cleanliness of mechanical elements included in the SMC manufacturing apparatus, preventing failure of control equipment installed in or around the SMC manufacturing apparatus, and preventing deterioration of the working environment.
It would be obvious to those skilled in the art that this effect becomes higher as the following gaps decrease: gap G1 between the inner circumferential surface of the circular opening (right) 53a of the side cover (right) 53 and the cylindrical circumferential surface of the roll body-adjoining part (right) 513, and gap G2 between the inner circumferential surface of the circular opening (left) 54a of the side cover (left) 54 and the cylindrical circumferential surface of the roll body-adjoining part (left) 514.
The gaps G1 and G2 are each, for example, 10 mm or less, preferably 5 mm or less, more preferably 3 mm or less, even more preferably 1 mm or less, and may be 0.5 mm or less. The gaps G1 and G2 are usually smaller than the length of the pin 510b and are preferably ½ or less thereof, more preferably ⅕ or less thereof, even more preferably 1/10 or less thereof (provided that the length of the pin 510b in this context is that of the longest pin when not all the pins have the same length).
The benefit obtained by suppressing the leakage of fiber dust to the outside of the side cover is particularly large when the short fiber bundle 2 comprises carbon fiber. This is because the carbon fiber generally has a small filament diameter of less than 10 μm, and therefore generates fine, floatable fiber dust. Another reason is that fiber dust generated from the carbon fiber is electrically conductive, and therefore can impede the operation of electrical and electronic equipment.
The gaps can be reduced to about 0.2 mm by using a metal for one of materials of the inner circumferential surface of the circular opening 53a, 54a and the cylindrical circumferential surface of the roll body-adjoining part 513, 514, while using a resin for the other.
A preferred example of the resin mentioned here is a resin generally used as a material for slide bearings, such as a polytetrafluoroethylene resin (PTFE), polyacetal, nylon, polyethylene, a phenol resin, polyimide, polyphenylene sulfide, polyetheretherketone, and polyamideimide.
The side cover 53 may be assembled from a plurality of parts, and the same applies to the side cover 54.
In the example shown in
In one example, when preparing the dispersion roller device 50, the roll body-adjoining part (right) 513 is first inserted into the hole 532a of the ring 532, and then the ring 532 is fixed to the cover main body 531. During this fixing process, the position of the ring 532 is adjusted so that the inner circumferential surface of the hole 532a and the roll body-adjoining part (right) 513 do not come into contact with each other. In order to enable such adjustment, the position of the ring 532 when fixed to the cover main body 531 is variable within a plane perpendicular to the rotation axis of the dispersion roll 51. This measure is particularly advantageous when preparing the dispersion roller device 50 in which the gap G1 between the cylindrical circumferential surface of the roll body-adjoining part 513 and the hole 532a of the ring 532 is small.
The cover main body 531 is preferably a metal plate. The material of the ring 532 may be the same as or different from that of the cover main body 531.
When the material of the ring 532 is resin, it is preferable that at least the cylindrical circumferential surface of the roll body-adjoining part 513 is formed of a metal.
When the material of the ring 532 is a metal, it is preferable that at least the cylindrical circumferential surface of the roll body-adjoining part 513 is formed of a resin.
The roll body-adjoining part 513 may be composed of two or more parts, and for example, a portion including the cylindrical circumferential surface and the other portions may be formed of different materials.
The descriptions presented above with reference to
In order to allow the side cover 53 to work more effectively, it is preferable that the vertical distance Du from the rotation axis of the dispersion roll 51 to the upper edge of the side cover 53 is larger than the maximum radius rM of the roll body 510 in the dispersion roll 51 (see
Similarly, it is preferable that the vertical distance DL from the rotation axis of the dispersion roll 51 to the lower edge of the side cover 53, the horizontal distance DF from the rotation axis of the dispersion roll 51 to the front edge of the side cover 53, and the horizontal distance DB from the rotation axis of the dispersion roll 51 to the rear edge of the side cover 53 are each larger than the maximum radius rM of the roll body 510.
The same applies to the side cover 54, and it is preferable that the vertical distances from the rotation axis of the dispersion roll 51 to the upper and lower edges of the side cover 54 and the horizontal distances from the rotation axis of the dispersion roll 51 to the front and rear edges of the side cover 54 are each larger than the maximum radius rM of the roll body 510.
As shown in
A seam may be present between the side covers 53, 54 and the front cover 55, and the same applies to the border between the side covers 53, 54 and the rear cover 56.
As shown in
In another example, as shown in
A small portion of the short fiber bundles 2 as well as the fiber dust generated from the short fiber bundles 2 may pass through the circular holes formed in the regulator plates 57, 58, but hardly leak to the outside of the side covers 53, 54.
In the first modified embodiment, the number of dispersion rolls provided in the dispersion roller device is two or more. Every one of the two or more dispersion rolls is provided with a roll body-adjoining part having a cylindrical circumferential surface, and the cylindrical circumferential surface is configured to face the inner circumferential surface of a circular opening provided in the side cover.
In a preferred example, the dispersion roller device may be provided with two dispersion rolls aligned one behind the other.
In order for more short fiber bundles to be struck by the pins 5101b, 5102b provided on the roll body 5101 of the rear dispersion roll and the roll body 5102 of the front dispersion roll when passing through between these roll bodies, it is preferable that, as shown in
The sum of the maximum radius rM1 of the roll body of the rear dispersion roll and the cylinder radius rc2 of the roll body 5102 of the front dispersion roll, and the sum of the cylinder radius rei of the roll body 5101 of the rear dispersion roll and the maximum radius rM2 of the roll body of the front dispersion roll are both smaller than the distance d12 between the rotational axes of the two dispersion rolls.
The arrangement in
The arrangement shown in
Further, the sum of the maximum radius rM1 of the roll body in the rear dispersion roll and the maximum radius rM2 of the roll body in the front dispersion roll may be slightly smaller than the distance d12 between the rotating axes of the two dispersion rolls. However, the difference {d12−(rM1+rM2)} is preferably 10 mm or less, more preferably 5 mm or less.
When two dispersion rolls aligned one behind the other are provided in the dispersion roller device, it is preferable that, as shown in
In the second modified embodiment, the roll body of the dispersion roll in the dispersion roller device is altered from pin roll type to cage roll type.
A cage roll type roll body has a structure in which a plurality of rods extending in the direction of the rotation axis are arranged at equal intervals on a cylinder surface centered on the rotation axis. The rods move in the circumferential direction when the dispersion roll is rotated, which allows the short fiber bundles to be struck by the side surfaces of the rods. Taut wires may be used instead of the rods.
The material of the rods is preferably a metal. The cross-sectional shape of the rods is not limited, and may be circular, oval, square, rectangular, hexagonal, or any of various other shapes.
The cage roll type roll body may have a superimposed structure formed by combination of the above-mentioned structure, that is, a structure in which a plurality of rods extending in the direction of the rotation axis are arranged at equal intervals on each of two or more concentric cylinder surfaces having mutually different radii.
Referring to
The roll body 510 comprises six round bars 510c spanned between a support member 513a included in the roll body-adjoining part (right) 513 and a support member 514a included in the roll body-adjoining part (left) 514. Since the six round bars 510c are arranged at equal intervals on a cylindrical surface centered on the central axis of the shaft 511, the roll body 510 has 6-fold rotational symmetry.
The diameter of the round bars 510c is, for example, 3 mm or less, may be 1.5 mm or less, and may be 1 mm or more.
The maximum radius rM of the roll body 510, that is, a radius of a cylinder whose central axis coincides with the rotation axis of the roll body 510 and which circumscribes the roll body 510 (a cylinder circumscribing the six round bars 510c) may be, for example, in the range of 100 mm or more and 200 mm or less, but is not limited thereto.
The roll body-adjoining part (right) 513 comprises a support member 513a and a disk 513b, and the roll body-adjoining part (left) 514 comprises a support member 514a and a disk 514b. When the dispersion roll 51 is built into the dispersion roller device, the cylindrical circumferential surface of the disk 513b faces the inner circumferential surface of the circular opening (right) provided in the side cover (right), and the cylindrical circumferential surface of the disk 514b faces the inner peripheral surface of the circular opening (left) provided in the side cover (left).
The radius of the cylindrical circumferential surface of the disk 513b, 514b is preferably equal to or larger than the maximum radius rM of the roll body 510.
The diameter of the cylindrical circumferential surface of the disk 513b, 514b may be significantly smaller than the diameter of the support member 513a, 514a, which, however, may pose a disadvantage that the gap formed between the support member 513a, 514a and the side cover 53, 54 is easily contaminated with fiber dust, and is not easily cleanable.
In one example, the support member 513a, 514a may also serve as the disk 513b, 514b. That is, when the dispersion roll 51 is built into the dispersion roller device, the inner circumferential surface of the circular opening (right) provided in the side cover (right) faces the cylindrical circumferential surface of the support member 513a, and the inner circumferential surface of the circular opening (left) provided in the side cover (left) faces the cylindrical circumferential surface of the support member 514a.
When the roll body 510 is of a cage roll type, the horizontal distance from each of the side covers 53, 54 to the roll body 510 may be 60 mm or less, 50 mm or less, 40 mm or less, 30 mm or less, 20 mm or less, or 10 mm or less.
The roll body of the dispersion roll in the dispersion roller device is not limited to the pin roll type or the cage roll type, as long as it has n-fold rotational symmetry around its rotation axis, with the proviso that the n is a finite integer of 1 or more. The n is preferably 2 or more and 72 or less, or may be 3 or more, and may be 36 or less or 24 or less.
For example, the roll body may be a triangular prism whose cross section perpendicular to the rotation axis is an equilateral triangle, or may have a shape in which such a triangular prism is twisted about the rotation axis. These are examples of the roll body having 3-fold rotational symmetry around its rotation axis.
As shown in
The maximum radius of the roll body is defined as the radius of a cylinder of which centerline is the rotation axis of the roll body and which circumscribes the roll body, regardless of the structure of the roll body.
The radii of the cylindrical circumferential surfaces of the roll body-adjoining parts individually adjoining one end and the other end of the roll body in its axial direction may preferably be equal to or larger than the maximum radius of the roll body 510.
The procedure for manufacturing SMC using the SMC manufacturing apparatus 10 is explained as follows.
First, a continuous fiber bundle 1 is drawn out from a fiber package prepared in advance. The continuous fiber bundle 1 may be drawn out from a bobbin package on a creel by unwinding from outside, or may be drawn out from a package from which a bobbin has been pulled out by unwinding from inside.
The continuous fiber bundle 1 preferably, but not exclusively, comprises carbon fiber, and may be one which is formed of fiber other than carbon fiber, such as glass fiber and aramid fiber.
When the continuous fiber bundle 1 is a carbon fiber bundle, the filament number per bundle may be, but is not limited to, 3,000 to 100,000, for example. The continuous fiber bundle may be partially split into a plurality of sub-bundles in advance.
A plurality of continuous fiber bundles 1 are aligned parallel to each other, and then supplied to a chopper 40 from a direction perpendicular to the T direction to be cut into short fiber bundles 2.
When manufacturing CF-SMC, the fiber length of the short fiber bundles 2 is, for example, 5 mm to 100 mm, preferably 10 mm to 60 mm, more preferably 10 mm to 30 mm, and typically 0.5 inch (about 1.3 cm), 1 inch (about 2.5 cm), 2 inches (about 5.1 cm), etc., but is not limited thereto.
In a modified example, instead of using the chopper 40 to produce short fiber bundles 2 from continuous fiber bundles 1 on the spot, a hopper or the like may be used in order for short fiber bundles 2 prepared beforehand in a separate process to fall from above onto the dispersion roller device 50.
The short fiber bundles 2 fall onto the first carrier film 4a while being dispersed by the dispersion roller device 50 to form a fiber mat 3.
When manufacturing CF-SMC, the operating condition of the dispersion roller device 50 (rotation speed of the dispersion roll 51) may preferably be set so that a fiber bundle with filament number of 500 or less and a single filament are not generated, or even when they are generated, the amount thereof in the fiber mat 3 is suppressed to less than 1% by weight.
Even when manufacturing CF-SMC, in an instance where the continuous fiber bundle 1 is a carbon fiber bundle that has been partially split into a plurality of sub-bundles in advance, and the filament number of each sub-bundle is less than 2K, the operating condition of the dispersion roller device 50 may preferably be set so that generation of fiber bundles with filament number of 0.2K or less is prevented as much as possible, and, even if generated, the amount of such fiber bundles in the fiber mat 3 is suppressed to less than 1% by weight.
Further, when manufacturing CF-SMC, it is desirable to determine the operating condition of the dispersion roller device 50 also in consideration of ensuring that the areal weight of the fiber mat 3 does not become significantly non-uniform due to the airflow generated by the rotation of the dispersion roller 51.
In an embodiment in which the dispersion roller device 50 has two pin roll type dispersion rolls arranged side by side with their rotational axes parallel to each other, when each dispersion roll is, as shown in
The reason is that both the heavy short fiber bundles and the light short fiber bundles fall onto the first carrier film through the gap between the roll bodies of the two dispersion rolls. In other words, the position at which the heavy short fiber bundles fall and the position at which the light short fiber bundle fall are less likely to shift along the travelling direction of the first carrier film.
Before depositing the fiber mat 3, a first resin paste 5a is applied to the first carrier film 4a using a first applicator 20.
The first resin paste 5a is a thermosetting resin composition, and examples of its base resins include, but are not limited to, a vinyl ester resin (also referred to as an epoxy acrylate resin), an unsaturated polyester resin, an epoxy resin, a polyimide resin, a maleimide resin and a phenolic resin. A mixed resin of a vinyl ester resin and an unsaturated polyester resin may also be used as the base resin. A curing agent, a polymerization inhibitor, a thickener, a reactive diluent, a low shrinkage agent, a flame retardant, an antibacterial agent, etc. are blended into the first resin paste 5a as necessary.
In a separate process, a second resin paste 5b having the same composition as the first resin paste 5a is applied to a second carrier film 4b using a second applicator 30.
The second carrier film 4b with its surface coated with the second resin paste 5b facing downward is superposed on the first carrier film 4a having the fiber mat 3 placed on its upper surface, and the resulting stack 7 is pressurized with an impregnator 60 to impregnate the fiber mat 3 with the thermosetting resin composition, thereby forming a resin-impregnated fiber mat.
The resin-impregnated fiber mat is wound onto a bobbin while remaining sandwiched between the first carrier film 4a and the second carrier film 4b. A sheet molding compound is completed after the process of thickening the resin-impregnated fiber mat.
Sheet molding compounds are used for molding FRP (fiber reinforced plastic) products using, for example, a compression molding method. In particular, the applications of CFRP products that can be manufactured using CF-SMC are wide-ranging, and include parts used in aircraft, unmanned aircraft, automobiles, ships, and various other transportation equipment, as well as sporting goods and leisure goods.
Preferred embodiments of the present invention include, but not limited to, the following.
[Embodiment 1] A method of manufacturing a sheet molding compound, comprising (i) allowing short fiber bundles to fall onto a carrier film travelling with its surface oriented approximately horizontally, while dispersing the short fiber bundles using a dispersion roller device having a rotationally driven dispersion roll, two bearings supporting the dispersion roll, a first side cover, and a second side cover, thereby depositing a fiber mat on the carrier film, and (ii) impregnating the fiber mat with a thermosetting resin composition, wherein the dispersion roller device has a configuration in which the first side cover and the second side cover are disposed between the two bearings; the dispersion roll comprises a roll body, a first roll body-adjoining part, and a second roll body-adjoining part, wherein the roll body comprises a cylinder and a plurality of pins provided on a circumferential surface of the cylinder, and the first roll body-adjoining part and the second roll body-adjoining part respectively adjoin one end and the other end of the roll body in its axial direction; and an inner circumferential surface of a circular opening provided in the first side cover and a cylindrical circumferential surface of the first roll body-adjoining part face each other, while an inner circumferential surface of a circular opening provided in the second side cover and a cylindrical circumferential surface of the second roll body-adjoining part face each other.
[Embodiment 2] The method of manufacturing according to Embodiment 1, wherein a diameter of the cylindrical circumferential surface of the first roll body-adjoining part and a diameter of the cylindrical circumferential surface of the second roll body-adjoining part are equal to that of the cylinder.
[Embodiment 3] The method of manufacturing according to Embodiment 1, wherein a diameter of the cylindrical circumferential surface of the first roll body-adjoining part and a diameter of the cylindrical circumferential surface of the second roll body-adjoining part are larger than that of the cylinder.
[Embodiment 4] The method of manufacturing according to any of Embodiments 1 to 3, wherein the cylinder has a diameter of 30 mm to 300 mm, preferably 60 mm to 150 mm.
[Embodiment 5] The method of manufacturing according to any of Embodiments 1 to 4, wherein the dispersion roll has a shaft penetrating through the roll body, the first roll body-adjoining part and the second roll body-adjoining part in its axial direction, and a diameter of the shaft is smaller than that of the cylinder.
[Embodiment 6] The method of manufacturing according to any of Embodiments 1 to 5, wherein a gap between the inner circumferential surface of the circular opening provided in the first side cover and the cylindrical circumferential surface of the first roll body-adjoining part, and a gap between the inner circumferential surface of the circular opening provided in the second side cover and the cylindrical circumferential surface of the second roll body-adjoining part are both smaller than a length of the longest pin among the plurality of pins.
[Embodiment 7] The method of manufacturing according to any of Embodiments 1 to 6, wherein the dispersion roller device has a first dispersion roll and a second dispersion roll, each as the dispersion roll, which are arranged side by side so that their rotation axes are parallel to each other.
[Embodiment 8] The method of manufacturing according to Embodiment 7, wherein the first dispersion roll is rotationally driven such that its pins move downward from above on its side facing the second dispersion roll, and the second dispersion roll is rotationally driven such that its pins move downward from above on its side facing the first dispersion roll.
[Embodiment 9] The method of manufacturing according to Embodiments 7 or 8, wherein a sum of a maximum radius of the roll body of the first dispersion roll and a maximum radius of the roll body of the second dispersion roll is greater than a distance between the rotation axes of the first dispersion roll and the second dispersion roll.
[Embodiment 10] A method of manufacturing a sheet molding compound, comprising (i) allowing short fiber bundles to fall onto a carrier film travelling with its surface oriented approximately horizontally, while dispersing the short fiber bundles using a dispersion roller device having a rotationally driven dispersion roll, two bearings supporting the dispersion roll, a first side cover, and a second side cover, thereby depositing a fiber mat on the carrier film, and (ii) impregnating the fiber mat with a thermosetting resin composition, wherein the dispersion roller device has a configuration in which the first side cover and the second side cover are disposed between the two bearings; the dispersion roll comprises a roll body, a first roll body-adjoining part, and a second roll body-adjoining part, wherein the roll body has n-fold rotational symmetry around its rotation axis, with the proviso that the n is a finite integer of 1 or more and may be 72 or less, and the first roll body-adjoining part and the second roll body-adjoining part respectively adjoin one end and the other end of the roll body in its axial direction; and an inner circumferential surface of a circular opening provided in the first side cover and a cylindrical circumferential surface of the first roll body-adjoining part face each other, while an inner circumferential surface of a circular opening provided in the second side cover and a cylindrical circumferential surface of the second roll body-adjoining part face each other.
[Embodiment 11] The method of manufacturing according to Embodiment 10, wherein a radius of the cylindrical circumferential surface of the first roll body-adjoining part and a radius of the cylindrical circumferential surface of the second roll body-adjoining part are equal to or greater than a maximum radius of the roll body.
[Embodiment 12] The method of manufacturing according to Embodiment 10 or 11, wherein the roll body is cage roll type, and has a plurality of rods or wires spanned between a support member contained in the first roll body-adjoining part and a support member contained in the second roll body-adjoining part.
[Embodiment 13] The method of manufacturing according to any of Embodiments 1 to 12, wherein the inner circumferential surface of the circular opening provided in each of the first side cover and the second side cover is made of a resin, and the cylindrical circumferential surface of each of the first roll body-adjoining part and the second roll body-adjoining part is made of a metal.
[Embodiment 14] The method of manufacturing according to any of Embodiments 1 to 12, wherein the inner circumferential surface of the circular opening provided in each of the first side cover and the second side cover is made of a metal, and the cylindrical circumferential surface of each of the first roll body-adjoining part and the second roll body-adjoining part is made of a resin.
[Embodiment 15] The method of manufacturing according to Embodiment 13 or 14, wherein the resin comprises any selected from a tetrafluoroethylene resin, polyacetal, nylon, polyethylene, a phenol resin, polyimide, polyphenylene sulfide, polyetheretherketone, and polyamide-imide.
[Embodiment 16] The method of manufacturing according to any of Embodiments 1 to 15, wherein a gap between the inner circumferential surface of the circular opening provided in the first side cover and the cylindrical circumferential surface of the first roll body-adjoining part, and a gap between the inner circumferential surface of the circular opening provided in the second side cover and the cylindrical circumferential surface of the second roll body-adjoining part are both 10 mm or less, 5 mm or less, 3 mm or less, 1 mm or less, or 0.5 mm or less.
[Embodiment 17] The method of manufacturing according to any of Embodiments 1 to 16, wherein the dispersion roller device satisfies at least one of conditions (A) and (B) below:
[Embodiment 18] The method of manufacturing according to Embodiment 17, which further comprises providing the dispersion roller device, wherein in the providing of the dispersion roller device, when the dispersion roller device satisfies the condition (A), the first roll body-adjoining part is inserted through the hole of the first ring, followed by fixing the first ring to the first cover main body, while when the dispersion roller device satisfies the condition (B), the second roll body-adjoining part is inserted through the hole of the second ring, followed by fixing the second ring to the second cover main body.
[Embodiment 19] The method of manufacturing according to Embodiments 17 or 18, wherein when the dispersion roller device satisfies the condition (A), a position of the first ring fixed to the first cover main body is variable within a plane perpendicular to the rotation axis of the dispersion roll, while when the dispersion roller device satisfies the condition (B), a position of the second ring fixed to the second cover main body is variable within a plane perpendicular to the rotation axis of the dispersion roll.
[Embodiment 20] The method of manufacturing according to any of Embodiments 1 to 19, wherein a vertical distance from the rotation axis of the dispersion roll to each of upper and lower edges of the first side cover, a horizontal distance from the rotation axis of the dispersion roll to each of front and rear edges of the first side cover, a vertical distance from the rotation axis of the dispersion roll to each of upper and lower edges of the second side cover, and a horizontal distance from the rotation axis of the dispersion roll to each of front and rear edges of the second side cover are each larger than a maximum radius of the roll body.
[Embodiment 21] The method of manufacturing according to any of Embodiments 1 to 20, wherein a pair of regulator plates are disposed between the first side cover and the second side cover in parallel to the travelling direction of the carrier film, and the roll body of the dispersion roll is passed through both an opening in one of the pair of regulator plates and an opening in the other one of the pair of regulator plates.
[Embodiment 22] The method of manufacturing according to Embodiment 21, wherein the opening in one of the pair of regulator plates and the opening in the other one of the pair of regulator plates are both circular and have a radius larger than a maximum radius of the roll body.
[Embodiment 23] The method of manufacturing according to any of Embodiments 1 to 22, wherein the short fiber bundles comprises carbon fiber.
[Embodiment 24] A dispersion roller device used for dispersing short fiber bundles allowed to fall onto a carrier film in production of a sheet molding compound, comprising a rotational drive dispersion roll, two bearings supporting the dispersion roll, a first side cover, and a second side cover, wherein: the first side cover and the second side cover are disposed between the two bearings; the dispersion roll comprises a roll body, a first roll body-adjoining part, and a second roll body-adjoining part, wherein the roll body comprises a cylinder and a plurality of pins provided on a circumferential surface of the cylinder, and the first roll body-adjoining part and the second roll body-adjoining part respectively adjoin one end and the other end of the roll body in its axial direction; and an inner circumferential surface of a circular opening provided in the first side cover and a cylindrical circumferential surface of the first roll body-adjoining part face each other, while an inner circumferential surface of a circular opening provided in the second side cover and a cylindrical circumferential surface of the second roll body-adjoining part face each other.
[Embodiment 25] The device according to Embodiment 24, wherein a radius of the cylindrical circumferential surface of the first roll body-adjoining part and a radius of the cylindrical circumferential surface of the second roll body-adjoining part are equal to that of the cylinder.
[Embodiment 26] The device according to Embodiment 24, wherein a radius of the cylindrical circumferential surface of the first roll body-adjoining part and a radius of the cylindrical circumferential surface of the second roll body-adjoining part are larger than that of the cylinder.
[Embodiment 27] The device according to any of Embodiments 24 to 26, wherein the cylinder has a diameter of 30 mm to 300 mm, preferably 60 mm to 150 mm.
[Embodiment 28] The device according to any of Embodiments 24 to 27, wherein the dispersion roll has a shaft penetrating through the roll body, the first roll body-adjoining part and the second roll body-adjoining part in its axial direction, and a diameter of the shaft is smaller than that of the cylinder.
[Embodiment 29] The device according to any of Embodiments 24 to 28, wherein a gap between the inner circumferential surface of the circular opening provided in the first side cover and the cylindrical circumferential surface of the first roll body-adjoining part, and a gap between the inner circumferential surface of the circular opening provided in the second side cover and the cylindrical circumferential surface of the second roll body-adjoining part are both smaller than a length of the longest pin among the plurality of pins.
[Embodiment 30] The device according to any of Embodiments 24 to 29, wherein the dispersion roller device has a first dispersion roll and a second dispersion roll, each as the dispersion roll, which are arranged side by side so that their rotation axes are parallel to each other.
[Embodiment 31] The device according to Embodiment 30, wherein the first dispersion roll is rotationally driven such that its pins move downward from above on its side facing the second dispersion roll, and the second dispersion roll is rotationally driven such that its pins move downward from above on its side facing the first dispersion roll.
[Embodiment 32] The device according to Embodiment 30 or 31, wherein a sum of a maximum radius of the roll body of the first dispersion roll and a maximum radius of the roll body of the second dispersion roll is greater than a distance between the rotation axes of the first dispersion roll and the second dispersion roll.
[Embodiment 33] A dispersion roller device used for dispersing short fiber bundles allowed to fall onto a carrier film in production of a sheet molding compound, comprising a rotational drive dispersion roll, two bearings supporting the dispersion roll, a first side cover, and a second side cover, wherein: the first side cover and the second side cover are disposed between the two bearings; the dispersion roll comprises a roll body, a first roll body-adjoining part, and a second roll body-adjoining part, wherein the roll body has n-fold rotational symmetry around its rotation axis, with the proviso that the n is a finite integer of 1 or more and may be 72 or less, and the first roll body-adjoining part and the second roll body-adjoining part respectively adjoin one end and the other end of the roll body in its axial direction; and an inner circumferential surface of a circular opening provided in the first side cover and a cylindrical circumferential surface of the first roll body-adjoining part face each other, while an inner circumferential surface of a circular opening provided in the second side cover and a cylindrical circumferential surface of the second roll body-adjoining part face each other.
[Embodiment 34] The device according to Embodiment 33, wherein a radius of the cylindrical circumferential surface of the first roll body-adjoining part and a radius of the cylindrical circumferential surface of the second roll body-adjoining part are equal to or greater than a maximum radius of the roll body.
[Embodiment 35] The device according to Embodiment 33 or 34, wherein the roll body is of a cage roll type, and has a plurality of rods or wires spanned between a support member contained in the first roll body-adjoining part and a support member contained in the second roll body-adjoining part.
[Embodiment 36] The device according to any of Embodiments 24 to 35, wherein the inner circumferential surface of the circular opening provided in each of the first side cover and the second side cover is made of a resin, and the cylindrical circumferential surface of each of the first roll body-adjoining part and the second roll body-adjoining part is made of a metal.
[Embodiment 37] The device according to any of Embodiments 24 to 35, wherein the inner circumferential surface of the circular opening provided in each of the first side cover and the second side cover is made of a metal, and the cylindrical circumferential surface of each of the first roll body-adjoining part and the second roll body-adjoining part is made of a resin.
[Embodiment 38] The device according to Embodiment 36 or 37, wherein the resin comprises any selected from a tetrafluoroethylene resin, polyacetal, nylon, polyethylene, a phenol resin, polyimide, polyphenylene sulfide, polyetheretherketone, and polyamide-imide.
[Embodiment 39] The device according to any of Embodiments 24 to 38, wherein a gap between the inner circumferential surface of the circular opening provided in the first side cover and the cylindrical circumferential surface of the first roll body-adjoining part, and a gap between the inner circumferential surface of the circular opening provided in the second side cover and the cylindrical circumferential surface of the second roll body-adjoining part are both 10 mm or less, 5 mm or less, 3 mm or less, 1 mm or less, or 0.5 mm or less.
[Embodiment 40] The device according to any of Embodiments 24 to 39, which satisfies at least one of conditions (A) and (B) below:
[Embodiment 41] The device according to Embodiment 40, wherein when the condition (A) is satisfied, a position of the first ring fixed to the first cover main body is variable within a plane perpendicular to the rotation axis of the dispersion roll, while when the condition (B) is satisfied, a position of the second ring fixed to the second cover main body is variable within a plane perpendicular to the rotation axis of the dispersion roll.
[Embodiment 42] The device according to any of Embodiments 24 to 41, wherein a vertical distance from the rotation axis of the dispersion roll to each of upper and lower edges of the first side cover, a horizontal distance from the rotation axis of the dispersion roll to each of front and rear edges of the first side cover, a vertical distance from the rotation axis of the dispersion roll to each of upper and lower edges of the second side cover, and a horizontal distance from the rotation axis of the dispersion roll to each of front and rear edges of the second side cover are each larger than a maximum radius of the roll body.
[Embodiment 43] The device according to any of Embodiments 24 to 42, wherein a pair of regulator plates are disposed between the first side cover and the second side cover in parallel to the travelling direction of the carrier film, and the roll body of the dispersion roll is passed through both an opening in one of the pair of regulator plates and an opening in the other one of the pair of regulator plates.
[Embodiment 44] The device according to Embodiment 43, wherein the opening in one of the pair of regulator plates and the opening in the other one of the pair of regulator plates are both circular and have a radius larger than a maximum radius of the roll body.
[Embodiment 45] Use of the device of any one of Embodiments 24 to 44 in a sheet molding compound manufacturing apparatus.
[Embodiment 46] The use according to Embodiment 45, wherein the sheet molding compound manufacturing apparatus comprises two applicators, a laminator and an impregnator.
[Embodiment 47] The use according to Embodiment 46, wherein the sheet molding compound manufacturing apparatus further comprises a chopper.
[Embodiment 48] A sheet molding compound manufacturing apparatus comprising the device of any one of Embodiments 24 to 44.
[Embodiment 49] The sheet molding compound manufacturing apparatus according to Embodiment 48, which further comprises two applicators, a laminator and an impregnator.
[Embodiment 50] The sheet molding compound manufacturing apparatus according to Embodiment 49, which further comprises a chopper.
[Embodiment 51] A method of manufacturing a sheet molding compound, comprising using the sheet molding compound manufacturing apparatus of any of Embodiments 48 to 50.
[Embodiment 52] The method of manufacturing according to Embodiment 51, which is a method of manufacturing a CF-SMC.
The present invention is described above with reference to specific embodiments. However, each embodiment is presented as an example, and does not limit the scope of the present invention. Each embodiment described in the present specification can be modified in various ways within the scope not departing from the concept of the invention, and can be combined with characteristics described in other embodiments to the extent practicable.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-118818 | Jul 2021 | JP | national |
| 2022-050649 | Mar 2022 | JP | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2022/021029 | May 2022 | WO |
| Child | 18407539 | US |
